Propeller blade cleaning apparatus



March 6, 1956" J. E; BIELER PROPELLER BLADE CLEANING APPARATUS Filed Aug. 27, 1952 RH u mm B #15 ATM/INDY) United States Patent 6 2,737,192 PROPELLER BLADE CLEANING APPARATUS John E. Bieler, Brookville, Ohio, assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application August 27, 1952, Serial No. 306,625

3 Claims. (Cl. 134-467) The present invention relates to cleaning apparatus, and more particularly to apparatus for cleaning the cavities of hollow propeller blades.

Heretofore the problem of removing extraneous material from hollow propeller blade cavities prior to coating thereof has been of easy solution. This was due primarily to the fact that the propeller blades were not twisted along their longitudinal extent so as to render the cavities inaccessible to conventional washing or cleaning apparatus. However, with the advent of blades, the airfoil sections of which are twisted between the root and tip sections thereof for aerodynamic purposes, the task of removing extraneous material from the blade cavities has become difficult. In fact, conventional washing or cleaning apparatus has virtually been rendered obsolete. Accordingly, one of my objects is to provide means for cleaning substantially inaccessible blade cavities that are obscured from vision.

The aforementioned and other objects are accomplished in the present invention by providing nozzle means so constructed and arranged that the reaction forces at; tendant with the flow of fluid therethrough cause movement of the nozzle and its associated flexible fluid conduit into the heretofore inaccessible blade cavities. Specifically the apparatus includes a reel assembly, which the flexible hoses or conduits normally encircle. Opposite extremities of each flexible hose are connected respectively to a source of suitable cleaning fluid under pressure and a nozzle. The nozzle is so constructed that the direction of fluid flow'therethrough is substantially reversed at is traverses the distance between the inlet opening and the outlet orifices thereof whereby the resultant reaction forces cause movement of the nozzle and its associated flexible hose along the inner periphery of the twisted blade cavity. The reel assembly is equipped with a spring device that controls the rate of movement of the nozzles and hoses into the blade cavities to assure adequate cleaning of the cavity walls. Valve means are provided for controlling the flow of fluid passing through the nozzles, and when the flow therethrough is discontinued by actuation of the valve means, the spring device rewinds the hose upon the reels. A rack is provided for insertion and support within the hollow root portion of the propeller blade to be cleaned to properly align the nozzles with respect to the blade cavities. The rack further provides a support for the nozzles and hoses when fluid flow therethrough is discontinued by actuation of the valve means.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing wherein a preferred embodiment of the present invention is clearly shown.

In the drawing:

Fig. 1 is a view in perspective of cleaning apparatus constructed according to the present invention, shown in combination with a hollow propeller blade.

Fig. 2 is a sectional view of a nozzle utilized in conjunction with the present invention.

Fig. 3 is a sectional view taken along line 3-3 of Fig. 2.

Figs. 4 through 7 are sectional views taken on lines 44, 5-5, 6-6, and 77, respectively, of Fig. 1 illustrating sections of the twisted airfoil portion with reference to the blade shank at a number of blade stations.

The cleaning apparatus, with which the present invention is directed to, is exemplified in conjunction with a propeller blade for purposes of example only, as it will be appreciated that the apparatus can easily be adapted for use in cleaning other articles having cavities which are inaccessible with the use of conventional cleaning apparatus. Referring particularly to Fig. l, the apparatus includes a reel assembly 10 rotatably journaled on a tubular member 11. As disclosed, the reel assembly has provision for supporting the coils of three flexible hoses, 12, 13 and 14. One end of each of the hoses, not shown, is connected to an opening in the tubular member 11 through which fluid under pressure is admitted from a pipe 15 through a manually controlled valve 16. The reel assembly 10 and the tubular member 11 may be supported by a stand including leg portions 17 and 18, as is shown in the drawing. The end of tubular member 11, which is not connected through the valve 16 to the pipe 15, is closed by a suitable plug 19. The reel assembly is provided with an axially projecting pin 20 about which one end of a torsion spring 21 is attached, the other end of the spring being attached to the tubular member 11 by any suitable means, not shown. The torsion spring 21 functions to retard movement of the reel device in the direction of the arrow 22, and movement in this direction winds the spring up whereby the spring 21 will eifect movement of the reel assembly 10 in the direction opposite to that of arrow 21 to rewind the flexible hoses or conduits upon the reel assembly when the force tending to produce movement thereof in the direction of arrow 22 is discontinued.

Referring to Fig. 2, the free end of each hose is connected to a nozzle 23. The nozzle is provided with the usual nipple portion 24, which is connected in fluid-tight engagement with the end of the hose. The nozzle 23 is provided with an inlet opening in the passage 25, which terminates in a flared head portion 26. Referring particularly to Figs. 2 and 3, the flared head portion is provided with a chamber 27 connecting the inlet passage 25 with a plurality of outlet openings or orifices 28. The chamber 27 is so constructed to change the direction of fluid flow from the inlet passage 25 to the outlet orifices 23 whereupon the reaction forces produced by this change of direction of the fluid flow tends to move the nozzle 23 and its associated hose axially of the nozzle.

The reaction forces, caused by changing the direction of fluid flow through the nozzle 23, are utilized in the present invention to produce movement of the nozzles and their associated hoses into cavities which heretofore have been practically inaccessible. The necessity for apparatus of this character arose with the production of hollow propeller blades having twisted airfoil portions. In the manufacture of propeller blades using ferrous metal parts, the interior-surfaces of the blade are coated with oxidation inhibiting material. Prior to the coating of the blade cavity walls, it is necessary to thoroughly clean the surfaces to remove rust deposits and any other extraneous material which may have accumulated during the manufacturing process. Prior to the adoption of propeller blades having twisted airfoil sections, cleaning of the cavity walls was accomplished by inserting perforated tubes within the blade cavities and discharging cleaning fluid through the openings thereof. This apparatus and method were feasible and quite satisfactory where the airfoil sectrons of the propeller blades lie in substantially the same plane. However, in the propeller blades of the type having airfoil sections that are twisted to a helix angle for aerodynamic purposes, conventional cleaning apparatus can no longer be used.

Referring particularly to Figs. 4 through 7, cross sections of a propeller blade taken at various stations along its longitudinal axis are depicted to illustrate the twisted airfoil section thereof. The sections, shown in Figs. 5 through 7, are all taken with reference to a horizontal line 29, shown in Fig. 4. The propeller blade includes a shank portion 3t and an airfoil section 31. The specific propeller blade shown is of the type including a thrust member 32 having leading and trailing edge portions and a: plurality of upstanding ribs. The cavities between the ribs and the leading and trailing edge portions are closed by a camber sheet 33, which is brazed through leading edge portions, as well as the ends of the upstanding ribs, to complete the-airfoil section.

in order to adapt the cleaning apparatus, including the reel assembly It and the flexible hoses with their attached nozzles, to clean the cavity walls of a hollow propeller "blade, a rack 34. is retained by any suitable means. not shown within the hollow shank portion 3d of. the propeller blade, to be cleaned. The rack 34 is provided with a plurality of openings through which the hoses 12;, 13 and 14 extend. However, the flared end of the nozzles 23 will not pass through the openings of the rack 34. The rack 34 performs two functions when the apparatus is used for cleaning propeller blade-cavities, namely: to support the nozzles within the blade when valve 16 is closed, and to properly align the nozzles with the open ends of the blade cavities which communicate with the shank portion 36 of the blade. it isto-be understood that the tip portion of the blade is sealed prior to cleaning of the blade cavities.

The operation of the apparatus, when used to clean propeller blades, is as follows. The rack 34 is inserted into the hollow shank portion of the blade and suitably secured therein. The valve 16 is then opened to admit cleaning fluid under pressure to the ends of the flexible hoses through the tubular member 11. The particular cleaning fluid used may vary with the article being cleaned and forms no part of the present invention. For example, the fluid may take the form of a vapor blast supplied from a source not shown to a pipe 15, which then traverses the tubular member 11 and the flexible hoses 12, 13, and 14 and discharges through the outlet orifice-s of the nozzles. As the flow of cleaning fluid under pressure through the nozzles is substantially reversed between the inlet passages 25 and the outlet orifices thereaction forces will move the nozzles and their associated "hoses into the cavities with which they a gned. in order to retard the rate of movement of the nozzles their hoses into the cavity, the spring device 22 is provided on the reel assembly It in this manner, adequate cleaning of the cavity walls can ained by re sting the fluid flow into tubular mems v, valve in. The nozzles will travel frm the shank. end of the blade to the tip end thereof, thereby tensioning the spring 21. When movement of the flexible hoses ceases due to engagement of the nozzles with the end of the blade cavities, the operator closes the valve .56 whetthev torsion spring 21 will wind the flexible hoses on the reel assembly 1 2 and reposition the nozzles 23 upon the rack 34. The rack 3-4 may then be moved from the blade which has been cleaned to successive'stations to clean additional blades.

From the foregoing, it is readily apparent that the present invention provides apparatus which may be used to cleancavities which areinaccessible with conventional fit cleaning apparatus. Moreover, the apparatus disclosed is of simple design and is extremely easy to operate.

While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted.

\Vhat is claimed is as follows:

1. Apparatus for cleaning cavities in articles, the cavities being obscured from vision due to the configuration of the article including, a rotatably journaled reel, a flexible conduit encircling said reel, opposite ends of said flexible conduit being connected to a nozzle and a source of cleaning fluid under pressure, said nozzle being adapted for insertion into a cavity and having an inlet opening and a plurality of outlet openings, passage means within said nozzle interconnecting the inlet and outlet openings and changing the direction of flow from the inlet to the outlet openings whereby the resultant reaction forces will cause movement of said nozzle and conduit relative to said article to elfect cleaning of the cavity walls, and means operatively connected with said reel for controlling the. rate of movement of said nozzle and flexible conduit relative to said article.

2'. A apparatus for cleaning cavities in articles including, a rotatably journaled reel, a flexible conduit encircling said reel, opposite ends of said flexible conduit being connected to a nozzle and a source of cleaning fluid under pressure, said nozzle being adapted for insertion into a cavity and having an inlet opening and a plurality of outlet openings, passage means within said nozzle interconnecting the inlet and outlet openings and changing the direction of flow from the inlet to the outlet openings whereby the resultant reaction forces will cause movement of said nozzle and conduit relative to said article to eflect cleaning of the cavity, manually operable valve means in the connection between said flexible conduit and the source of fluid pressure for controlling the flow of fluid therethrough, and a torsion spring device operatively associated with said reel for controlling the rate of movement of said nozzle and flexible conduit relative to said article and for automatically rewinding the flexible conduit on the reel upon the interruption of fluid flow through the nozzle by actuation of the valve means.

3. Apparatus for cleaning cavities in articles including, a rotatbly journaled reel, a flexible conduit encircling said reel, opposite ends of said flexible conduit being connected to. a nozzle and a source of cleaning fluid under pressure, said nozzle being adapted for insertion into a cavity and having an inlet. opening and a plurality of outlet openings, passage means within said nozzle interconnecting the inlet and outlet openings and changing the direction of flow from the inlet to the outlet opening whereby the resultant reaction forces will cause movement of said nozzle and conduit relative to said article to effect cleaning of the cavity, means operatively connected with said reel for. controlling the rate of movement of said nozzle and flexible conduit relative to said article, and a rack insertable in the article cavity, said rack providing a support for the nozzle in the absence of fluid flow therethrough.

References Cited in the file of this patent UNITED STATES PATENTS 440,838 Chapman Nov. 18, 1890 1,176,518 Burns Mar. 21, 1916 1,444,889 Sladden Feb. 13, 1923 1,537,637 Jarvis Mar. 12, 1925 

